The end justifies the means. By any means necessary. These are slogans people hear regularly, and despite their brevity actually represent a school of thought in moral philosophy. If a particular outcome is just, the argument goes, then whatever it takes to secure that end is therefore also just.

This is the utilitarian approach.

Opponents of this theory counter that there must be boundary conditions on how a goal is achieved, and that justice requires that those conditions be satisfied even if that jeopardizes the goal. Concepts like “rights” or “fairness” are common to this other approach. People tend to have conflicting intuitions about these—on the one hand, we want effectiveness, but on the other, we want fairness. A lot of superhero fiction explores this tension.

In the film Captain America 2: The Winter Soldier, SHIELD’s plan is to have satellite-based pre-emptive strikes against threats to global security. When this is framed as “protecting our freedoms,” Captain America demurs, noting that it actually reduces freedom to kill people before they’ve had a trial, before they’ve even committed a crime.

As it turns out, SHIELD had been infiltrated by the evil organization Hydra, but their plan to abuse the system for their own ends only underscores that even some of the good guys thought the basic idea was sound. As one of the bad guys asks, if you can kill 20 million to increase the safety of six billion, then it’s a good trade, isn’t it? (Similarly, in the first Avengers movie, the military is ordered to nuke New York City in order to forestall an alien invasion. The Avengers do not agree that this is the just way to handle the situation, and Iron Man risks his life to find another solution.)

But one might object that the 20 million have rights—the right not to be killed, the right to be given as much chance at life as the rest. Does respecting their rights make it hard to provide perfect security and order? Perhaps. The other short slogan that’s relevant to this debate is more familiar to lawyers and Latinists: Fiat justitia ruat caelum or “Let justice be done though the heavens fall.” In other words, the consequences do not necessarily warrant doing bad things in their service.

In a recent episode of the “Agents of SHIELD” television series, Daisy and Mac argue about this very issue. Daisy thinks that the best way to find out where the terrorists they’ve been pursuing are meeting is to use physical coercion against a person they know to be an associate of the group. Mac bristles at this suggestion, pointing out that such a use of force makes it hard to tell why they’re the good guys. Daisy wins the argument, and threatens a man, using her powers to bust up his truck until he tells her what she wants to know. Mac walks away, visibly  disappointed in his partner’s ethics.

Many superheroes define themselves in terms of a line not to be crossed—typically drawing the line at killing people. This has been in evidence in the current season of the “Daredevil” television series. Daredevil, like all the other costumed vigilante crime-fighters, beats up bad guys, but he draws the line at killing them. He has a moral commitment to the absolute value of human life, which he doesn’t see as his prerogative to take away. So he will incapacitate and deliver bad guys to the legal system, but he will not kill. His new “frenemy” The Punisher, on the other hand, is perfectly content to kill them. Daredevil argues with him about this, noting that their right to life is inviolate, even if they belong in prison for life. The Punisher’s point is that the world is better off with them dead, so he might as well kill them.

It’s pretty clear that these issues are not confined to the fantasy realm of science fiction and superheroes. As is often the case, the fictional settings allow us to explore the issues in a thought-provoking yet safe manner, bringing them into greater relief. Does the end justify the means? It’s hard to see how rights could be a meaningful concept if that were true. Why not beat suspects until they confess? Why bother with search warrants? Why not have pre-emptive killing of threats?

A free society in a pluralistic world won’t be possible without treating persons as having rights to live and not to be used as a stepping-stone to others’ goals, no matter how well-intentioned.